1. Field of the Invention
This invention relates to seating devices.
More particularly, the present invention relates to adjustment mechanisms for seating devices.
In a further and more specific aspect, the present invention concerns adjustment mechanisms for vehicle seating.
2. The Prior Art
Within the art of recliner mechanisms for vehicle seating, many and diverse devices have been developed. These devices often function satisfactorily for the actual reclining function, but function poorly in the area of safety. Typically, when a force of a specific magnitude, such as from a collision, is applied to a seat back, the seat has a catastrophic failure. In other words, the seat back remains more or less rigid and supportive until a certain level of force is exceeded. When this level is reached, the recliner mechanism breaks, letting the seat back pivot unrestrained. When this failure occurs, injury to the occupant of the seat can result. In many automobiles, the space allocated for a recliner mechanism is very limited. By reducing size and cost, current recliner mechanisms are often less than robust and fail at the application of relatively low forces. With the increase of restraint belts, which attach to the seat back, forces applied to the seat back in a collision will only increase.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object the present invention to provide a recliner mechanism which is extremely rugged and which fixedly holds the seat back relative to the seat portion.
It is another object the present invention to provide an embodiment of the recliner mechanism which clutches under a specified load.
Briefly, to achieve the desired objects of the present invention in accordance with a preferred embodiment thereof, provided is a recliner mechanism for a seat frame including a back portion and a seat portion. The recliner mechanism includes an internal conically shaped element attached to either the back portion or the seat portion and a mating external cylindrical element attached to the other of the back portion and the seat portion. A first portion of the inner surface of the cylindrical element is conically tapered with circumferentially extending gear teeth thereon and a second portion is designed to form a first journal contact area. The outer surface of the conically shaped element has circumferentially extending mating gear teeth on a first portion and a second portion is designed to form a first mating journal contact area. The second portion of the inner surface of the cylindrical element and the second portion of the outer surface of the conically shaped element cooperate to form a first mating journal for maintaining axial alignment between the conically shaped element and the cylindrical element during relative axial movement therebetween. In one embodiment, the first mating journal contact areas are positioned at one end of the gear teeth and second mating journal contact areas are positioned at the opposed end of the gear teeth. The axial length of the first and or second mating journal contact areas is greater than the relative axial movement between the cylindrical element and the conically shaped element so that one or both of the journals maintain axial alignment between the cylindrical element and the conically shaped element during relative axial movements. In this fashion the two sets of gear teeth are always in proper axial alignment for easy and accurate movement between a disengaged position and an engaged position.